On two cephalaspid molluscs (Gastropoda: Opisthobranchia) with two gizzard plates, and description of a new genus and a new family

E.M. Chaban & P.V. Kijashko

Abstract. The morphology of the soft body of two unique cephalaspid species, Eоscaphander fragilis Habe, 1952 and Cylichna magna Lemche, 1941, having two gizzard plates in their gizzards has been studied. Taxonomic position of the both species is discussed. The morphology of E. fragilis is described and illustrated for the first time. The species belongs to the monotypic genus which was considered previously as a junior synonym of the genus Scaphander. Feeding of E. fragilis on sponges has been noted. A new monotypic genus, Pseudocylichna gen. nov., has been described for Cylichna magna. Morphological differences of the gizzard plates and gizzard walls of the genera mentioned before have been shown. Both genera have been placed in a new family Eoscaphandridae fam. nov. based on their pair gizzard plates and the division of the gizzard wall into four segments by tendons of the connective tissue.

Key words: opisthobranch molluscs, morphology, taxonomy, north-western part of Pacific Ocean, north of Atlantic Ocean, Eoscaphandridae, Eoscaphander, Pseudocylichna, new family, new genus

Zoosystematica Rossica, 2016, 25(2): 204–215 ▪ Published in print 27 December 2016

https://doi.org/10.31610/zsr/2016.25.2.204 ▪ Open full article

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